OVER the past 10 years, an increasing interest in surgery of epilepsy has led to the development of progressively more effective methods of evaluation. At the same time, most researchers in this field have realized that the surgery usually comes too late, when the devastating effects of the disease have already left the patient with irreparable psychological scars. In the Cleveland Clinic Foundation Epilepsy Program, patients had surgery 13.6 years after seizure onset and 11.3 years after the seizures became medically intractable. This delay has led to a growing interest in identifying suitable surgical candidates at an earlier stage, which could lead to more timely surgical intervention. Plans to perform surgery at an earlier stage should naturally take into consideration the following questions. Can we reliably identify children suffering from intractable epilepsy which will remain intractable even with maturation? Are the work-up methods currently used in adults also applicable in children, or do we need to develop a completely new technique of evaluation for children? Are the results of surgery in children as successful as those in adults?

We will describe here the system of presurgical electroencephalographic (EEG) evaluation currently in use at the Cleveland Clinic Foundation, and then try to answer some of these questions. Only surgery of epilepsy in patients with partial epilepsies will be discussed. Surgical treatments used preferentially for generalized epilepsies, such as corpus callosotomy, are taken up elsewhere in this issue (see Spencer and Spencer).